UPDATE at 8:55am
Power is restored. City Light explained, " In attempting to reroute power to restore a portion of the original customers with another feeder (major power line), the second feeder relayed out. So, a second block of customers was without power for about ten minutes, including the Westwood neighborhood. At its height, the outages affected approximately 11,000 customers."

UPDATE at 7:00am
The City Light system status still shows 723 customers out at 7am.
http://www.seattle.gov/light/sysstat/

UPDATE at 6:40am
City Light crews responded quickly to a power outage that knocked out the lights for more than 3200 customers in West Seattle's Gatewood Hill. For a time the traffic signals at 35th and Thistle and Holden were out. The outage extended down to include the West Seattle Thriftway store at Morgan Street.
Power was restored for many shortly before 6:30 am.

UPDATE at 6:10 am
City Light has released a statement about the West Seattle power outage:
"The outage was first reported at approximately 4:30 a.m., Sunday, November 11, 2012. Crews are responding to determine the cause and make repairs. The boundaries are on the north SW Findlay Street; on the south SW Henderson Street.; on the east 28th Avenue SW; and on the west, Puget Sound. At this time there is not an estimate time of restoration. "

Original Post
A power outage that started around 4:22am in West Seattle has affected portions of Gatewood Hill and extended in a patchy fashion around the area, affecting 3265 City Light customers.

There is no known cause for the outage at this time.

Estimated repair time is 11am.

You can monitor the system status on City Light's page for that purpose here:

http://www.seattle.gov/light/sysstat/